The present invention relates to a facsimile machine having a memory unit and a stacker.
Facsimile machines with internal memory units are well known. Small amounts of memory are used for purposes such as transmit and receive buffering, and storing image data while the data are being coded and decoded. Larger internal memories store multiple pages of image data, enabling the image data to be received and printed at different speeds, or at different times, and enabling documents to be scanned and transmitted at different speeds or times.
Facsimile machines that deliver printed pages into a stacker are also well known. The printed pages may have been transmitted from a distant facsimile machine, or they may have been scanned by the facsimile machine itself, in which case the facsimile machine operates as a copier. The printed pages accumulate in the stacker until they are removed manually.
The capacity of the stacker differs from one facsimile machine to another, but in any case, the printed pages should be removed often enough to keep the stacker from becoming full. If the stacker can stack no more than fifty pages, for example, then the printed pages should be removed before fifty pages have been stacked. If the stacker is allowed to become full, then when the next printed page is delivered into the stacker, it jams against the pages that have already been stacked, typically causing a facsimile transmission to fail, and occasionally putting the facsimile machine out of order by damaging the printing mechanism.
It is accordingly an object of the present invention to avoid paper jams and associated problems that occur when a facsimile machine attempts to deliver printed pages to a full stacker.
Another object of the invention is to enable a facsimile transmission to continue while the stacker is full, and to print the received pages as soon as the stacker is emptied.
Another object is to resume a suspended document copying operation as soon as the stacker is emptied.
The invented method of controlling a facsimile machine comprises the steps of:
counting the printed pages delivered to the stacker;
suspending printing when the page count reaches a limit value;
sensing the presence and absence of printed pages in the stacker; and
resuming printing when the stacker is sensed to be empty.
The invented facsimile machine has a memory unit that stores the limit value, a paper sensor that performs the sensing step, and a control unit that performs the other steps.